Transmitters for radio telephone base stations
First Claim
1. A transmitter for a radio telephone base station, the transmitter being operative to transmit radio signals on at least two channels, the transmitter comprising a variable gain preamplifier for each channel, combining means for combining the outputs of the variable gain preamplifiers, a multichannel power amplifier for amplifying the output of the combining means, coupling means for sampling the output of the multi-channel power amplifier and for obtaining a sampled signal representative of the output power on each channel, and a feedback loop for applying to each variable gain preamplifier a control signal which is derived from the said sampled signal, whereby the gain of each preamplifier is varied in dependence upon the power level of each channel at the output of the multichannel power amplifier.
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Accused Products
Abstract
A multi-channel transmitter has a variable gain preamplifier (8a, 8b, 8c) for each channel, the combined outputs being fed to a linearized multi-channel power amplifier (10). The output of the latter is sampled by coupling means (12) which produce a sampled signal representative of the power in each channel. The sampled signal is applied to a frequency selective feedback loop which, for each channel, provides a control signal (20a, 20b, 20c) applied to the corresponding preamplifier (8a, 8b, 8c) to vary the gain of the latter in order to provide separate power control for each channel.
31 Citations
5 Claims
- 1. A transmitter for a radio telephone base station, the transmitter being operative to transmit radio signals on at least two channels, the transmitter comprising a variable gain preamplifier for each channel, combining means for combining the outputs of the variable gain preamplifiers, a multichannel power amplifier for amplifying the output of the combining means, coupling means for sampling the output of the multi-channel power amplifier and for obtaining a sampled signal representative of the output power on each channel, and a feedback loop for applying to each variable gain preamplifier a control signal which is derived from the said sampled signal, whereby the gain of each preamplifier is varied in dependence upon the power level of each channel at the output of the multichannel power amplifier.
Specification